1. The Field of the Invention
The present invention relates generally to a medical device, and, more particularly, to a surgical instrument assembly for reducing and removing tissue masses from a body during minimally invasive procedures, such as laparoscopic surgery.
2. Description of the Related Art
In the past, the standard procedure for removing a large tumor, diseased organ or tissue mass from a patient was accomplished by open surgery. As a result of the open surgery, patients commonly suffered postoperative pain, long hospital stays, long recovery periods, and large scars where the incisions were made.
With the advent of minimally invasive surgery, such as, for example, laparoscopic surgery, large tissue masses may be removed by making smaller incisions, decreasing postoperative pain and hospitalization time and providing a faster return to functional status for the patient as compared to open surgery.
In recent years, there has been an unprecedented increase in the number of patients undergoing treatment with interbody devices for segmenting or snagging the large tumor, diseased organ or tissue mass to be removed. The use of various devices during laparoscopic surgery has amplified the surgeon""s precision and quality and has shortened the length of operative procedures.
One method of reducing the size of large tissue masses in a body cavity is to use a device such as a morcellator. A morcellator is used in conjunction with a tissue isolation bag to mechanically reduce the size of the object by grinding, coring or shaving the object. However, morcellators are generally very slow, which increases the risk and cost associated with the operating procedure, and frequently do not remove tissue in identifiable form to allow later pathology.
Other methods of reducing the size of large tissue masses include use of a surgical snare or wire cage to retrieve, segment or cut the tissue mass by the combination of mechanical forces and heat. However, the tissue mass frequently escapes from the capturing instrumentality or is damaged beyond identifiable form. In addition, the tissue mass frequently jams against the end of the trochar inserted into the bag for delivering the device, disrupting the procedure.
3. Summary of the Invention
The invention provides a device and a method that overcome these problems and results in a higher quality of minimally invasive surgery. In addition to providing better quality reduction or segmentation control, the invention offers a quicker and more economical procedure as compared to known minimally invasive procedures and devices.
According to one embodiment, a device for reducing tissue mass comprises an isolation bag surrounding the tissue mass. The bag has an inner conductive layer which constitutes a first electrode. The device also comprises a trochar extending into the isolation bag and a probe introduced into the bag through the trochar to contact the tissue mass. The probe constitutes a second electrode. A power source supplies electrical current to the probe and the inner layer of the bag. A current bridge is created through the tissue mass between the probe and the inner layer of the bag so that the probe effectively ablates or vaporizes the tissue mass.
According to another embodiment, a device for segmenting tissue mass comprises an isolation bag having an open end. The bag is capable of being introduced into a body cavity while in a collapsed state and of being expandable from the collapsed state to an expanded state to surround the tissue mass when inserted into the body cavity. The inside of the bag containing the tissue mass thermally and electrically insulated from the body cavity. The device also comprises a trochar having a distal cap end and a moveable proximal cap end and a cage of electrosurgical wires capable of surrounding the tissue mass. The wires have ends connected to the proximal cap end. The cage of electrosurgical wires are held in formation by the distal cap end of the trochar and retracted by moving the proximal cap end. The device also comprises a center rod passing through the trochar and into the bag and a source of electrical current for supplying current to the cage of electrosurgical wires and the center rod. The combination of the center rod and the cage of electrosurgical wires work to reduce and segment the tissue mass by both mechanical and electrosurgical means.
According to another embodiment of the invention, a device for reducing tissue mass in a body cavity comprises an insulated bag having an open end. The bag is capable of being introduced into the body cavity while in a collapsed state and being expandable from the collapsed state to an expanded state to surround the tissue mass. The open end of the bag containing the tissue mass is withdrawn from the body cavity. The device also comprises a trochar having a distal end and a wall comprising a right end cap, a left end cap, and a conductive surface on one side of the wall facing the tissue mass. The wall is deployable into the bag through the trochar. At least one wire loop is positioned within the bag. The loop has ends that pass through the right and left end caps of the wall. The device further comprises tensioning means for applying tension to at least one of the ends of the loop to reduce the diameter of the loop so that the tissue mass contacts the conductive surface of the wall. The device also comprises a source of electrical current for supplying current to the conductive surface and the wire loop. An electrical path is formed between the loop and the conductive surface. The combination of the loops and the conductive surface work to reduce or segment the tissue mass.
In another aspect, the invention is directed to a method for segmenting a tissue mass in a body cavity comprising steps of surrounding the tissue mass with an isolation bag, the isolation bag including an open end; withdrawing the open end of the isolation bag to the outside of the body cavity; and segmenting the tissue mass into a plurality of smaller pieces by creating an electrical path between at least one wire loop and a deployable electrically conducting surface by applying tension to the wire loops. In another aspect, the method comprises the step of segmenting the tissue mass into a plurality of smaller pieces by creating an electrical path between an electrically conducting inner layer of the isolation bag and a probe having at least one electrically exposed electrode.